The present disclosure relates generally to a method of co-molding. In particular, the disclosure relates to co-molding a first element and a second element to produce an article. The disclosure also relates to the article produced and to an article of footwear including the article.
Co-molding of two or more objects may be a convenient method for producing a unified article. The two or more separate objects may be adhered, cemented, melted, or otherwise associated with each other to produce a unified article. The association may be carried out in a mold, which ensures proper location of the individual objects in relationship with each other.
In co-molding, objects may be fully formed before being placed in the mold, or may be produced in place in the mold. The objects may be cemented together, melted together, or otherwise adhered to produce a unified article. For example, adhesive may be placed on the first elements before a second element is produced in place in the mold. In an article of footwear, the first element may be an outsole and the second element may be a fluid-filled chamber that may provide cushioning, for example, in the midsole.
After the article is produced, the article must be removed from the mold. Typically, removal of the article can be more difficult as the complexity of the mold increases. For example, areas in which inserted first elements closely contact the mold walls increase the difficulty in removing the article. Such areas may exist where it is necessary to ensure registration of a feature on one object with a feature on another object and, therefore, the objects must be held tightly to minimize movement.
The force required to remove an object from the mold also may be increased by the complexity of the objects. For example, an object comprising protuberances may be more difficult to remove from a mold. Such protuberances may be ground-engaging lugs on a shoe outsole, for example. Similarly, a small undercut in a mold may increase the difficulty in removing the article if, as may occur, the mold is not movable so as to accommodate removal of the area undercut.
Therefore, there exists a need in the art for an improved method of co-molding.